Sunday, September 20, 2015

The changing tides of war

How quickly can the tides of war change? At Grandmaster level it usually remains stable: Once one side gets the advantage, he or she can often hold onto it until the opponent is outplayed. But at amateur level, blunders occur more frequently, leading to greater swings in advantage. Sometimes, both sides make so many mistakes that the tides of war change more than the number of times our MRT system breaks down.

Image from SGAG

Which is precisely what happens in one of my online games: I went into the middlegame with an extra pawn, only to see my advantage vanish when my opponent sacrificed the exchange for a strong attack. Several moves later... his botched attack evaporated, with the advantage back in my hands in the endgame. So sit back, and enjoy this whopping 70-move struggle.

Opponent vs Checkerboard 5
Correspondence Chess 2015

1. Nf3 Nf6
2. d4 e6
3. g3 b6
4. Bg2 Bb7
5. c4 Be7
6. Nc3 O-O
7. O-O Ne4
8. Qb3 d6
9. Qc2?!

Moving a piece twice in the opening is not a wise thing to do.

9... Nxc3
10. Qxc3 c5
11. Bf4 cxd4
12. Qc2?

White is losing a pawn for nothing. Better was: 12. Nxd4 Bxg2 13. Kxg2 e5?! Here perhaps White had been afraid of the pawn fork. However, he would realize after deeper calculation that he has a strong refutation: 14. Nf5! Qd7 (14... exf4 15. Qxg7#) 15. e4 Bf6 16. Be3 with nice piece placement and attacking chances against the weak pawn on d6.

12... Nc6
13. a3 (D)

Position after 13. a3

13... e5!?

Black is up a pawn, but it is not very well protected. I decided to exploit my temporary material advantage by going for a central advance. This move, however, weakens the light squares in the centre as well, and gives White a potential outpost on d5. Better would be to complete development first before attacking the centre: 13... Rc8 14. Rfd1 Bf6 15. Rac1 (15. e3? e5 trapping the bishop.) 15... Qe7 threatening ...e5 followed by ...e4 gaining space in the centre.

14. Bd2 f5
15. e3 e4
16. Nxd4 Nxd4
17. exd4 Bf6
18. Rad1?!

18. Bc3 {followed by Rad1 was better.

18... Qe7?

Missing the chance to win back the pawn. I seriously wonder how I managed to completely overlook 18... Bxd4 19. Bg5 Qxg5 20. Rxd4. The pawn on d6 looks weak, but after20... Qe7 21. Rfd1 Rf6 Black holds and even has the threat of ... Rc8 followed by ... d5

19. Be3 Rac8
20. b4 d5?!

Allowing White to push c5.

21. c5

Now Black is in real danger of allowing a passed pawn on the c-file.

21... Ba6
22. Rfe1 Bd3

22... Bc4 Cutting off the c5 pawn from one of its defenders was better.

23. Qc1 Qd7
24. Qc3 Qa4 (D)

Position after 24... Qa4

Planning to infiltrate the Queenside via the light squares. However, I was caught off-guard with White's next move.

25. Rxd3!

Sacrificing the exchange to open up the position. After I recapture, my pawn structure falls apart.

25... exd3
26. Bxd5+ Kh8
27. Qxd3 Rfd8
28. Qxf5

With the Queen and the Bishop pair, White gets a strong attack against my king.

28... Qxa3
29. Be4 Kg8
30. Qxh7+ Kf8
31. Bg6 Qb3 (D)

Position after 31... Qb3

Forced. 31... Qxb4? 32. Qh8+ Ke7 33. Bd2+ loses the Queen.

32. Qh3

Of course 32. Qh8+ Qg8 33. Qxg8+? Kxg8 takes most of the steam out of White's attack. Remember: When defending, you should seek piece exchanges to weaken the attack.

32... bxc5
33. bxc5 Rc7
34. Rb1 Qd5
35. Bf5 Re7
36. Bf4 Bxd4
37. Bd6 Rxd6!

Earlier on White sacrificed the exchange for his attack. Now, I can afford to return my extra material to weaken the attack by getting rid of White's bishop pair.

38. cxd6 Qxd6
39. Qh8+ Kf7
40. Qh5+ Kg8

40... Kf6? loses after 41. Qg6+ Ke5 42. Re1+ Kd5 43. Be4+ while 40... g6 41. Bxg6+ Qxg6 42. Qxg6+ Kxg6 leaves White with a two-pawn advntage in the endgame.

41. Bh7+ Kf8
42. Rd1?!

42. Bg6 threatening Qh8# was better.

42... Qf6

With White's bishop pair gone I can make counterthreats of my own.

43. Rf1 Re1!

With the threat of ... Qxf2+. White is forced to trade queens and abandon his attack.

44. Qf5 Qxf5
45. Bxf5 Re2 (D)


I could have chosen to trade rooks (45... Rxf1+ 46. Kxf1) and simplify into a drawn opposite-colour bishop endgame. However, I avoided the trade as I realized that the rook was very strong on the 2nd rank. Combined with the bishop pin it ties down White's king and rook to defending f2, while his bishop is of the wrong colour and unable to assist. Although I am down a pawn, my active rook and the outside passed pawn on a7 has swung the advantage back in my favour.

46. Kg2 Ke7

Activating the king. Notice that with White's king tied to defending f2, I am effectively a piece up in this endgame.

47. Kf3 Rd2
48. Bg4 Kd6
49. Kg2 a5
50. Bd1 Kc5
51. h4 Kb4
52. Bh5 a4

The outside passed pawn is a decisive factor.

53. Bf7 a3
54. Rb1+ Kc5
55. Rf1

Or 55. Rc1+ Kd6 where White must retreat to defending f2.

55... a2
56. Bxa2

Forced.

56... Rxa2
57. Rc1+ Kd5
58. Rf1 Ke4

Now my king goes over to support the g7 pawn.

59. Re1+ Kf5
60. Rf1 Kg4

Covering f3 and g3, reducing White's options. Winning the f-pawn is only a matter of time.

61. h5 Rc2

61... Kxh5 62. Kf3 also wins, but White has more freedom here with the threat of g4+

62. h6! gxh6 (D)

Position after 62... gxh6

White also has devious plans of his own. With the earlier exchange I am left with a rook pawn, which reduces my winning chances.

63. Rd1 Bxf2
64. Kh1 Bxg3

White is willing to lose his pawns now. If he is able to trade rooks, the game will be a draw: A rook-pawn, and a wrong-coloured bishop which does not cover the pawn's promoting square, cannot win if the enemy king controls the promoting square. Careful play is needed here if I want to win.

65. Ra1

65. Rd4+ Bf4 66. Kg1 might have offered more resistance, but White's king is still trapped on the 1st rank and has no way to successfully trade rooks.

65... h5
66. Rb1 h4
67. Ra1 Kh3
68. Rf1??

Losing on the spot, but other moves also hold no future.. For example 68. Rd1 Rh2+ 69. Kg1 Bf2+ 70. Kf1 Rh1+ 71. Ke2 Rxd1 72. Kxd1 Kg2 and even though White has removed the rooks from the board, Black controls the promotion square and will win.

68... Rd2
69. Rb1

69. Kg1 Rg2+ 70. Kh1 Bf2 71. Rxf2 (71. Ra1 Rh2#) 71... Rxf2 72. Kg1 Kg3 73. Kh1 Rf1#

69... Rh2+
70. Kg1 Bf2+ (D)
0-1

Position after 70... Bf2+

The threat here after 71. Kf1 is 71... Rh1+ winning the rook.

Sources:
http://sgag.sg/posts/6-potential-transport-minister-and-what-funny-things-he-she-would-say-if-the-mrt-breaks-down

No comments:

Post a Comment